title: Differences in breathing patterning during wakefulness in patients with mixed apnea-dominant vs obstructive-dominant sleep apnea.
abstract: BACKGROUND
  Mixed apneas share both central and obstructive components and are often treated as if they are obstructive events. The hypothesis is that patients with obstructive sleep apnea syndrome (OSAS) who exhibit a majority of mixed apneas will differ in ventilatory control from those with predominantly obstructive apneas during wakefulness; moreover, this difference could affect nasal continuous positive airway pressure (CPAP) adherence.
  
  
  METHODS
  In a retrospectively derived case-control study, 5 min of respiratory inductance plethysmography signals during wakefulness prior to sleep onset were extracted from a diagnostic polysomnogram in these groups: (1) mixed apnea-dominant OSAS (mix-OSAS) (n = 36), (2) obstructive apnea-dominant OSAS (pure-OSAS) (n = 20), (3) central apnea-dominant sleep apnea syndrome (pure-CSAS) (n = 6), and (4) control subjects (n = 10). Breathing patterning was compared between the groups using the coefficient of variation (CV) for breath-to-breath inspiration time (TI), expiration time (TE), TI + TE (Ttot), and tidal volume, and an information theory-based metric of signal pattern variability (sample entropy). Subsequent CPAP adherence over 12 months was determined in OSAS groups.
  
  
  RESULTS
  Breath-to-breath CV parameters and sample entropy in the mix-OSAS group were significantly greater as compared with the pure-OSAS and control groups. In a subanalysis, CV and sample entropy were similar in the mix-OSAS and the pure-CSAS groups. CPAP adherence was significantly poorer in mix-OSAS compared with pure-OSAS.
  
  
  CONCLUSIONS
  During wakefulness, both breath patterning and sample entropy in mix-OSAS are similar to pure-CSAS and more variable than in pure-OSAS. In addition, CPAP adherence was decreased in patients with mix-OSAS, which may be related to basic differences in respiratory control.
authors.affiliation: Second Department of Internal Medicine, Department of Respiratory Medicine, Nara Medical University, Kashihara. Electronic address: motoo@naramed-u.ac.jp.
authors.forename: Motoo
authors.initials: M
authors.lastname: Yamauchi
authors.affiliation: Second Department of Internal Medicine, Department of Respiratory Medicine, Nara Medical University, Kashihara.
authors.forename: Shinji
authors.initials: S
authors.lastname: Tamaki
authors.affiliation: Second Department of Internal Medicine, Department of Respiratory Medicine, Nara Medical University, Kashihara.
authors.forename: Masanori
authors.initials: M
authors.lastname: Yoshikawa
authors.affiliation: Department of Internal Medicine, Tenri City Hospital, Tenri.
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Ohnishi
authors.affiliation: Department of Pulmonology, Fukuoka National Hospital, Fukuoka, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Nakano
authors.affiliation: Division of Pulmonary, Critical Care, and Sleep Medicine, Case Western Reserve University and Louis Stokes Cleveland VA Medical Center, Cleveland, OH.
authors.forename: Frank J
authors.initials: FJ
authors.lastname: Jacono
authors.affiliation: Department of Electrical Engineering and Computer Science, Case Western Reserve University, Cleveland, OH.
authors.forename: Kenneth A
authors.initials: KA
authors.lastname: Loparo
authors.affiliation: Division of Pulmonary, Critical Care, and Sleep Medicine, Case Western Reserve University and Louis Stokes Cleveland VA Medical Center, Cleveland, OH.
authors.forename: Kingman P
authors.initials: KP
authors.lastname: Strohl
authors.affiliation: Second Department of Internal Medicine, Department of Respiratory Medicine, Nara Medical University, Kashihara.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kimura
mesh_terms: D000328:Adult; D003937:Diagnosis, Differential; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D011379:Prognosis; D012119:Respiration; D012129:Respiratory Function Tests; D012189:Retrospective Studies; D012720:Severity of Illness Index; D020182:Sleep Apnea, Central / Q000175:diagnosis / Q000503:physiopathology*; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis / Q000503:physiopathology*; D014851:Wakefulness / Q000502:physiology*